The invention relates to a personnel detector, or an apparatus which detects the presence or absence of a personnel or personnels in personnel containment means such as a seat in a vehicle, a theater or audience hall.
A certain kind of vehicle is provided with a personnel detector for detecting the presence or absence of an occupant for purposes of preventing a failure to close side windows (including a window of a door located beside a driver's seat, an opposite window or located adjacent to an assistant driver's seat, and other windows of doors which are located directly behind the first mentioned windows) or a sunroof (roof panel), controlling outlet ports of an air conditioner and controlling a car audio set. Thus, when no occupant is detected, any open side window and/or sunroof is controlled so as to be closed. Alternatively, the presence or absence of a personnel is detected for each individual seat so that the direction of outlet ports of the air conditioner or the output balance of the car audio set may be controlled so as to serve the occupied seat or seats.
An occupant detector which is commonly used in a vehicle of the type includes a seating switch, which is embedded in each seat or chair so as to be closed when a personnel is seated thereupon.
Specifically, FIG. 23a is a cross section of an assitant driver's seat of a vehicle, comprising a seat cushion cover 30, a seat cushion pad 31, a pad support 32, a seat cushion spring 33 and a seat cushion frame 34. A seating switch 200 is embedded within the seat cushion pad 31.
FIG. 23b shows the detail of parts around the seating switch 200. In this Figure, it will be noted that the seating switch 200 essentially comprises a movable contact 201 and a stationary contact 202 which is secured to the pad support 32. Both the seat cushion pad 31 and the pad support 32 are formed of a flexible resilient material, and are adapted to flex as an occupant is seated thereupon. However, the seat cushion pad 31 is formed of a more pliable material such as urethane foam, and accordingly, the seat cushion pad 31 may flex relative to the pad support 32 in a manner indicated by phantom line in FIG. 23b. In response thereto, the movable contact 201 moves angularly about its pivot, thus moving into contact with the stationary contact 202 to cause the switch to turn on. The seating switch 200 is connected to an electrical circuit, not shown, so as to provide an indication that an occupant has seated upon the seat.
It will be understood that the disclosed seating switch 200 is mechanically opened and closed in response to the flexure of the seat cushion pad 31 as an occupant is seated. Hence, it is vulnerable by impacts, and is likely to cause faults, in particular, as the occupant gets on the vehicle to produce shocking forces. Because it includes mechanical contacts, it has reduced useful life. In addition, the switch will be turned on if a baggage other than a personnel is placed thereon, thus reducing the reliability of personnel detection.